Report an unroutable classifier cell as no_route

Dockerfile

@@ -2,7 +2,7 @@
 
 FROM python:3.12.14-slim-trixie@sha256:78387bc3881b8273120a12ebe6c1ab22b018ccc2c9adf565ae1ac9b536e184ea
 
-ARG VERSION=0.1.0
+ARG VERSION=0.1.1
 ARG VCS_REF=unknown
 ARG OPENAPI_SHA256
 ARG PIP_INDEX_URL=https://pypi.org/simple

openapi.yaml

@@ -1,7 +1,7 @@
 openapi: 3.1.0
 info:
   title: gh-aw-router HTTP API
-  version: 0.1.0
+  version: 0.1.1
   license:
     name: MIT
     identifier: MIT
@@ -81,6 +81,8 @@ paths:
         Model choices follow the embedded classification_choices list, filtered
         to exact offered models and efforts. The first returned choice is preferred.
         Reasoning models require an explicit effort. No default effort is inferred.
+        If no offered choice is in the classifier cell, the response is 422 with
+        code no_route. Malformed requests are still rejected with invalid_request.
       requestBody:
         required: true
         content:
@@ -103,7 +105,13 @@ paths:
         "415":
           $ref: "#/components/responses/UnsupportedMediaType"
         "422":
-          $ref: "#/components/responses/InvalidRequest"
+          description: >-
+            Request schema violation (invalid_json), unsupported operation
+            (invalid_request), or no eligible classifier choice (no_route).
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
         "500":
           $ref: "#/components/responses/InternalError"
         "504":

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "gh-aw-router"
-version = "0.1.0"
+version = "0.1.1"
 description = "Standalone classification planning and model routing service"
 readme = "README.md"
 license = "MIT"

src/gh_aw_router/__init__.py

@@ -1,3 +1,3 @@
 """Standalone gh-aw-router classification planning and model routing."""
 
-__version__ = "0.1.0"
+__version__ = "0.1.1"

src/gh_aw_router/classification.py

@@ -18,6 +18,7 @@
     TaskType,
     TextPart,
 )
+from gh_aw_router.routing import NoRouteError
 
 MAX_PRIOR_TURNS: Final = 6
 MAX_PRIOR_TURN_CHARS: Final = 400
@@ -108,8 +109,9 @@ def create_classification_plan(
     """Rank exact offered choices by the embedded classifier preference order.
 
     Preserve caller identities and prefer the first matching table entry. Raise
-    ClassificationError for missing authored text, omitted reasoning effort, or
-    an empty intersection. No provider calls or default-effort inference occur.
+    ClassificationError for missing authored text or omitted reasoning effort,
+    and NoRouteError when no offered choice is in the classifier cell. No
+    provider calls or default-effort inference occur.
     """
     authored = authored_messages(request.conversation)
     if not authored:
@@ -139,7 +141,7 @@ def create_classification_plan(
                 )
             )
     if not ranked:
-        raise ClassificationError("none of the available models is in the classifier routing cell")
+        raise NoRouteError("none of the available models is in the classifier routing cell")
     return ClassifyResponse(
         system_prompt=SYSTEM_PROMPT,
         prompt=build_classification_prompt(authored),

tests/fixtures/routing-contract/classify.json

@@ -21,7 +21,7 @@
       "conversation": [{"role": "user", "parts": [{"text": "Proceed."}]}],
       "models": []
     },
-    "status": 422, "response": {"code": "invalid_request", "detail": "invalid request: none of the available models is in the classifier routing cell"}
+    "status": 422, "response": {"code": "no_route", "detail": "no route: none of the available models is in the classifier routing cell"}
   },
   {
     "id": "classify-missing-effort", "method": "POST", "path": "/classify",
@@ -30,5 +30,13 @@
       "models": [{"id": "reasoning", "model": "github-copilot/router-reasoning"}]
     },
     "status": 422, "response": {"code": "invalid_request", "detail": "invalid request: reasoning effort must be specified for 'github-copilot/router-reasoning'"}
+  },
+  {
+    "id": "classify-unrecognised-choices", "method": "POST", "path": "/classify",
+    "request": {
+      "conversation": [{"role": "user", "parts": [{"text": "Proceed."}]}],
+      "models": [{"id": "absent", "model": "github-copilot/router-absent"}]
+    },
+    "status": 422, "response": {"code": "no_route", "detail": "no route: none of the available models is in the classifier routing cell"}
   }
 ]

tests/fixtures/routing-contract/discovery.json

@@ -3,7 +3,7 @@
   {
     "id": "capabilities", "method": "GET", "path": "/capabilities", "status": 200,
     "response": {
-      "name": "gh-aw-router", "version": "0.1.0",
+      "name": "gh-aw-router", "version": "0.1.1",
       "routing_profiles": [
         {"goal": "cost", "mode": "economy"},
         {"goal": "cost", "mode": "balanced"},

tests/test_classification.py

@@ -25,6 +25,7 @@
     RoutingModeRecommendation,
     TextPart,
 )
+from gh_aw_router.routing import NoRouteError
 
 
 def test_shared_classify_request_matches_policy_order(
@@ -109,7 +110,7 @@ def test_classification_requires_an_offered_routing_identity() -> None:
         models=(ModelChoice(id="other", model="provider/other"),),
     )
 
-    with pytest.raises(ClassificationError, match="none of the available models"):
+    with pytest.raises(NoRouteError, match="none of the available models"):
         create_classification_plan(request, (ModelArm(model="provider/preferred"),))
 
 

tests/test_cli.py

@@ -149,19 +149,21 @@ def test_validate_data_reports_the_loaded_table_summary() -> None:
     ]
 
 
+@pytest.mark.parametrize("command", ["route", "classify"])
 @pytest.mark.parametrize("unsupported", [False, True])
 def test_no_route_has_a_distinct_exit_status(
     planning_payload: Callable[[str], dict[str, Any]],
     synthetic_table_path: Path,
     unsupported: bool,
+    command: str,
 ) -> None:
-    request = planning_payload("route")
+    request = planning_payload(command)
     request["models"] = [{"id": "unsupported", "model": "provider/unknown"}] if unsupported else []
     stdout = io.StringIO()
     stderr = io.StringIO()
 
     status = run(
-        ["--routing-tables", str(synthetic_table_path), "route"],
+        ["--routing-tables", str(synthetic_table_path), command],
         stdin=io.StringIO(json.dumps(request)),
         stdout=stdout,
         stderr=stderr,
@@ -224,7 +226,7 @@ def test_parser_exposes_package_version(capsys: pytest.CaptureFixture[str]) -> N
         cli.build_parser().parse_args(["--version"])
 
     assert error.value.code == 0
-    assert capsys.readouterr().out == "gh-aw-router 0.1.0\n"
+    assert capsys.readouterr().out == "gh-aw-router 0.1.1\n"
 
 
 @pytest.mark.parametrize(